Structural design of “three-branch” flow tube for offshore blowout emergency rescue

A three-branch flow tube device was designed to deal with the blowout out of control accidents which happen on offshore production platforms. In the process of blowout emergency rescue by the source control method, it can lead fluid/flame upwards by virtue of “stack effect” to reduce the wellhead temperature, so that the safety of blowout emergency rescue is improved. The “three-branch” flow tube device is mainly composed of flow tube, suspension cylinder, main shaft, suspension unit, lock unit and support unit. During the operation, the angles and heights of three flow tubes can be adjusted according to wellhead distribution to support wire cable and cable hoist for blowout emergency rescue. Then, the structure of each part was illustrated and carry out finite element analysis on the structural strength and the hoisting under harsh working conditions. It is indicated that the device strength meets the requirement. During the gas well blowout at the rate of 200×104 m³/d, the maximum equivalent stress is 492 MPa and the maximum displacement is 348.02 mm; and in the environment of level 6 wind, the maximum equivalent stress is 495 MPa and the maximum displacement is 353.12 mm, which can all satisfy the demands of emergency rescue operations. The research results provide a reference for the research and development of flow tube used for the blowout emergency rescue of production platform.